Fuel supply system for helicopter with jet-driven rotor



Filed Aug. 3, 1946 Feb. 12, 1952 v lsAccg 2,585,468

FUEL SUPPLY SYSTEM FOR- HELICOPTER WITH JET-DRIVEN ROTOR 6 Sheets-Sheet l 1 1' E] E a 6 73a as as 82 am 0/ U U U INVENTOR Vittnrin Isaccu ATTORNEY Feb. 12, 1952 v. ISACCO 2,585,468

FUEL. SUPPLY SYSTEM FOR HELICOPTER WITH JET-DRIVEN ROTOR Filed Aug. 3, 1946 6 Sheets-Sheet 2 36 INVENTOR \fifinrm 155mm,

ATTORNEY Feb. 12, 1952 V. ISACCO FUEL SUPPLY SYSTEM FOR HELICOPTER WITH JET-DRIVEN ROTOR 6 Sheets-Sheet 3 Filed Aug. 5, 1946 IN VEN TOR ATTORNEY Feb. 12, V. ISACCQ FUEL SUPPLY SYSTEM FOR HELICOPTER WITH JET-DRIVEN ROTOR Filed Aug. 3, 1946 6 Sheets-Sheet 4 9'5 d INVENTOR V1 tturln 15 a cum BY ATTORNEY Feb. 12, 1952 v. lsA zco FUEL SUPPLY SYSTE FOR HELICOPTER WITH JET-DRIVEN ROTOR 6 Sheets-Sheet 5 Filed Aug. 5, 1946 ATTORNEY Feb. 12, 1952 v. ISACCO 2,535,463

FUEL. SUPPLY SYSTEM FOR HELICOPTER WITH JET-DRIVEN ROTOR Filed Aug. 5, 1946 6 Sheets-Sheet 6 /a INVENTOR" Vi'tt ur'i El Isaccn,

ATTORNEY Patented Feb. 12, 1952 UNITED. "STATES PATENT OFFICE.

, 2,585,468 FUEL SUPPLY SYSTEM FOR HELICOPTER WITH JET-DRIVEN ROTOR,

, Vi ttorio Isacco, l ondon, England Application August 3, 1946, Serial No. 688,269

' -In Great Britain August 3, 1945 One feature of the invention resides in the.pro-.

vision at or in the vicinity of the axis of rotation of the hub of the propeller, of an auxiliary fuel tank adapted to supply the fuel to engines on the blades. This tankor part of it may be stationary, the fuel being fed to. the engines by means comprising a distributer having a part rotatable with.

the propeller but theauxiliary tank is preferably rotatable as a whole with the propeller. A pump adapted to feed fuel to the auxiliary tank. from the main tank located in the fuselage isprovided and this pump is preferably driven bya drive transmission from the rotating propeller.

The advantage of the auxiliary tank as above set forth is that a single tank can be utilised for two or more engines and the weight of the rotor is less than it would be were the tanks in the ferred because they are more suitable for use with the sustaining driving rotor. 7 Other features of the present invention comprise the following:

1. The rotor blades are adapted to have a limited degree of flap by the provision of hinge joints at their root ends; and the axes of the hinges are preferably out of perpendicular in relation to the longitudinal axes of their respective blades in order to produce an automatic variation of the pitch angle of the blades when they are subjected to air over pressures, This variation is such that the pitch angle decreases when the blades are lifted and increases when they aredepressed. Such an automatically operating device ensures that the blades are not subjected to excessive stresses and, in addition, assists the stability of the machine when in translation flight. The degree of flap is preferably limited by resilient stops.

2. The following means areprovided either to ensure lateral and longitudinal stability of the machine or to enable the machine to be inclined in the direction of horizontal flight.

a. Ailerons adapted to be periodically varied as to pitch angle are mounted at the tips of the blades provided with propulsion means, either bel Claim. (cram-15.11)

: fore or after the saidmeans in the case of those blades provided with such propulsion means, said ailerons either being mounted so as to be turnable around axes coincident with the longitudinal axes of the respective blades or being mounted so as to be turnable around axes parallel with the said longitudinal axes, the said ailerons constituting continuations of the blades.

b. Blades which are not providedwith propul sion means are adapted to be difierentially varied as to pitch angle.

c. a and b in combination, i. e., applied to a rotor comprising both blades with engines and blades without engines.

3. Means adapted releasably to hold the rotor against turning said means being under the con-- trol of the pilot as to release of the-rotor and being provided to enable the propulsion means to be set into operation, one at .a time if necessary, without the rotor being driven. Such means may comprise a wire which is connected at one end to the fuselage and is releasably connected at its other end to a blade.

1 4. A vertical rudder which is adaptedto turn on a horizontal axis and on a, vertical axis, the movements taking place simultaneously in order, to enable the pilot to control the direction of the machine while hovering and while in horizontal flight. When the machine is hovering the in clination of they rudder around the horizontal axis will enable the pilot to produce the necessary couple for directing his machine around a vertical axis.

5. Blades, which may be limited as to flap upwards and downwards as set forth in '(1) above and provided with propulsion means are mounted so as resiliently to yield to drag pressures, such:

mounting permitted of only slight oscillation in the direction of drag pressure (i.e., in the plane ofrotor rotation).

6. A device which permits of the general pitch angle variation of the blades and of the periodical variation of the pitch angle for stability purposes by means of a single control lever solid with the inner tips of the blades.

The invention will now be described with reference to the accompanying drawings which are given by way of example for each case and whic comprise the following: I

a. Means for driving the rotor for the different practical sizes of the machine.

1). Means for feeding fuel and for controlling the jet propulsion units mounted on the blades. 0. Means for allowing the blades to rotate after the propulsion units have been started.

d. Means for controlling the lateral and longi tudinal stability of the machine or for inclining the machine in order to achieve horizontal flight; v

e. Necessary controls;

I. Means for attaching the blades to the rotating hub whether or not they are fitted with jet propulsion unitsg. Means-for compensating for thefriction of the rotating rotor, ball-bearing controls, and fuel pump on the central shaft of the machine or for assuring the control of the machine around a vertical axis, and V h. The general aspect of the machine in two types given as examples, the first when all-the blades are provided with engines, and the second when some of them are provided with engines.

In the said drawings:

Fig. 1 is a top view of the helicopter-with jet propulsion units mounted at the tips of the blades, the stability ailerons being located between-the-units and the blades. These ailerons constitute a prolongation of the blade. The horizontal elevator at the rear of the:fuselage is notindicated, as in certain cases it can be dispensed with.

Fig. 2 is a top view of thehelicopter withthe jet propulsion unitsmounted ononly twoof .the blades. In this machine'the stability is assured by a periodical variation of the pitch angle of the blades.

Fig. 3 is a sideview of the machine witha cable in position-to preventthe blades from rotating while the engines are started.

Fig. 4 is an example of the release device which allows the pilot to release the blades athis will afterthe propulsion units are started.

Fig. 5 is a general verticalcrossssection on the line -V-- V, Fig. 2- showingthe various. controls of the machine, the attachment of the blades to:the central hub when they carry no propulsion units, and the system of thefuel feeding of the. rotating propulsion units from amain tank located insidethe fuselage to the uppeinrotating auxiliary fuel tank and from-there to the propulsion uni-ts.

Figs. 6 and '7 are vertical and horizontahcross sections, respectively, showing .the .method of mountingthe-blades on the central hub for those blades which are provided with propulsion .units.

Fig. 8 is a top view of the mounting .of the blades comparable with Fig. 'lbut with theaxis of the horizontal joint not perpendicularztothe longitudinal axis of theblades.

Figs. 9, 10and 11 showrespectivelyatop view, a front view and a side view of the position and method of control (as an example) of the stability ailerons.

Fig. 1-2 is a perspective view showing, .more particularly, the system of wires-.andpulleysused to operate any of the controls andas well the device allowing the general pitch angle device and the-stability controls to operate simultaneouslyor separately on'the same tube ending the blades; and

Fig. 1-3 is a perspective view ofthe methodof controlling the vertical rudder of thefuselage, both around a vertical axis and around a. horizontal axis.

Figs. 1, 2 and 3, show the helicopter machine, constituted by a fuselage l, the usual landing gear 2 in the front and Satthe rear where are mounted also the usual elevator 4 (Fig.2 only) and the vertical rudder 5.

The elevator 6 can be eliminated in certain cases, and for that reason it is not indicated in Fig. 1. The vertical rudder 5 can rotate as usual around a vertical axis but'here it also rotates around a horizontal axis as will be described.

The object of the second'hinging movement of the elevator is to enable the air flow projected by the blades during rotation to be utilised in order to create accouple capable of -rotating the machine around its vertical central axis, thus allowing the pilot to direct his machine in any direction around the said axis (see Fig. 3).

On the central hub B of the blades, located above the fuselage l are mounted the blades 1 (Fig. l) and I, la (Fig. 2) of the sustaining and propulsive propeller.

Inside the central hub 6 and its extension 6a are located all the controls of the machine and the fuel reservoir as will be described.

In Fig. 1 all the blades are driven separately by jet propulsion units 18 mounted on their tips beyond .theistability ailerons 9 ,which ailerons constitute a;.prolongation. of the said'blades.

In Fig. 2 only-two. blades tare driven byunits 8, and the other blades la (two in thisexamplel are not fitted with engines. .The proportion of the blades provided with engines to those not so provided, depends .onthe available power ofthe engines v.andonthe sizeoi' the machine. TiliS is also. the .reason' why different methods are utilisedto stabilize orrtoincline the machine in the. requireddirection otflighaas .will be described.

In Fig. 2 .thestabilisingsystem isprovided by the periodical .or dlfierential variation of the pitch angle of the whole of each. blade la.

.The. periodical ordifierential variation of the pitch angleof the :ailerons or the blades consists in the variation of .the angle .of incidence of the blades or ailerons'periodically duringone .revolution, in such .a way, that the angle .of incidence becomesgreaterat .90 tQ-the side at which the inclination .of the machines .shaft is required, and smaller at from ithe position where the incidence-z is :greater. Between these two opposite positions and at:9G-.to eachof .them, the incidence shall not be altered.

In Figs. 3 and 4 is:.-shown an example of the means for releasingzthe rotating 'bladesfrom the fuselage to which .theyzhave to be previously attached in ordert-to start the :propulsion units. In the examplethe lower: end of av wire I l is, fixed at l2 -to the nose of :the fuselage and :the upper end'of the .wireisfixedto a loop 13. A belt l4 passes through the loopand hasa wire I5, which can be pulled in the direction of the arrow a by the pilot, attached to it. A spring [6 restores the bolt to its normal position when the wire .lfiis released. The body I! containing both the bolt l4 and the spring ['6 is attached at It and i811, to a hollow part of the blade llatthe .underpart thereof.

It will be clear that when the jet propulsion units are started and the. blades are required to rotate the pilot has to pull-the. wire I5. -When he does this thehcok l3 is-released .and the .wire

H falls. 'It maybeautomatically wound-up in.

to the hub 6. Leverszl9, [Scare .connected tolevers 1| hingedito legs-.22 on the control gball,

bearing system, the legs 22 being diametrically opposite each other.

The control ball bearing system comprises the following:

A ball bearing 23 is located between two cases 24 and 25 respectively and maintained in position by nuts 26, 26a. Case 25 can slide along the central shaft 21, this sliding movement being effected by means of a pin 28 passing through convenient slots 29 made in the central supporting shaft 21. The ends of the pin 28 are fixed with the case 25. The pin 28 is moved upwards or downwards by means of a double set of flexible wires 30, 36a, and 3|, 3m operated by the pilot, one wire of the set 30, 36a being attached to the pin 28 at 32 and the other set being attached to the pin at 33. In this manner the pin is operated on at-two opposite points simultaneously.

The way in which the wire are operated and the way in which they are located within the central shaft is shown in Fig. 12 and will be described hereinafter.

The operation of the ball bearing system is therefore as follows:

When the pin 28 is operated (pulled upwards or downwards) the whole system will slide along the central shaft 2'! and in addition the outer case 24 fixed with the outer ring of the ball bearing 23, the legs 22,, the levers l9, 19a and 21 will continue to rotate with the blades.

To pull the release wire l according to arrow a the pin 28 and therefore the ball bearing system have to be pulled-downwards.

a The operation of the other controls is similar.

In Fig. 5 above the release control is located the general pitch control ball bearing system 35 0f the blades but only for those blades which carry no propulsion units.

Another ball bearing system 36 similar to the previous-one is provided to vary the pitch angle of the blades Which are driven by jet propulsion units. The change of incidence requirements for blades carrying the engines as compared with those which carry no engine, can in certain cases be different, separate pitch angle variation controls are, therefore, provided.

In other cases, a single ball bearing control system can be provided for all blades, in this case the ball bearing system 36 is eliminated and the ball bearing 35 has four connecting rod 16 instead of two.

Above the previously described control, is shown the ball bearing systems 31 and 38 respectively of the engine throttle controls, one for each propulsion unit. In this example two blades with propulsion units are considered.

Finally, the last ball bearing control system 48 is shown above the others. This system is for the lateral or longitudinal control of the ailerons for stability purposes or for inclining the shaft of the machine in order to achieve horizontal night in the direction required.

This system does not slide along the shaft 2'! as do the others, but is mounted on this central shaft by means of gimbal joints 4! and 42 which enables universal inclination of the bearing system.

When the system 40 is inclined it is clearly seen that the rods 43 which are connected to the legs 44 of the exterior casing 45 of the bearing will be subject to upward and downwards movements during one revolution thus achieving what I have called a differential variation of the incidence of the ailerons during each revolution.

The rods 43 are connected to crank levers 46 which are fixed with their respective shafts. 46a and the shafts are fixed with straight levers 41 and 47a. Wires 48 and 48a are connected to the lever 41 and 41a which wires, after crossing inside the blades, operate the ailerons as is shown in Figs. 9, l0 and 11 and as will be described with reference thereto. Y

The pulleys around which pass the, wires operating the various ball bearing systems just described, are located on the top of the central shaft 21. In the drawing only two wires which operate the blades release device and the blades general incidence, are shown passing over the pulleys.

For the ball bearing systems which operate on I The hub 6 bears against the central shaft 21- by means of ball bearings 56 which can withstandboth radial and axial pressures. I

Fig. 5 shows also the fuel feeding system. .To the lower part of the hub 6 is fixed a spur wheel 5i which operates a pinion 52. The pinionfby means of a flexible transmission 53', drives the fuel pump 54. The fuel pump, located inside the fuselage I, takes fuel from the main tank 55 and delivers it to the upper rotating reservoir 56 through the tubes 5! and 51a according to the arrows d. The said tubes are suitably mounted inside the shaft 21.

The fuel reservoir 56'is fixed to the hub 6 by means of a'cylinder 51 and therefore both rotate with the hub 6. fixed to the central shaft 21, thereservoir 56 has to rotate around it. To avoid any leaking of fuel at the hole through which the tube 57apasses through the fuel reservoir 58, special joints are fitted as well as antifriction rings 58 and 59. This friction is very small.

The fuel inside the reservoir 56 rotates with it and by virtue of the centrifugal force and of gravity, since the reservoir 56 is located well above the blades and the engines, the fuel is carried from the reservoir 56 by tubes 66..and conducted by them inside the blades to the engines, according to arrows e. Joints 6| of conventional form and cocks 62 are fitted below the reservoir 56. I

The ignition system, comprising slip rings 63, carbon brushes 64, cables65 connected to the engines and cables 66 connected to switche inside the cockpit has already been described in my previous British Patent No. 332,312.

The roots of the blades la (the blades which are not provided with propulsion units) are at-' tached by means of a double joint articulation 61 and 68 to the hub. The vertical articulation 61 allows for lateral oscillation Which are strongly braked and limited by an elastic ring 69 fixed on extensions I0 of the hub 6. The horizontal component 68 is limited in its upward and downward oscillations by stops on the rubber ring 69.

The horizontal articulation ends with the tube II passing into the interior of a double thrust ball bearing 12 the outer race of which is mounted inside the hub 6. I

. Ring nuts 13 and 13a on hub 6 and 14 on'tube H maintain the ball bearing in position. :Onthe other side of each ball bearin 12 is fixed a lever 15 .(see also F 1,

The tubes 51 and 51a being i'Ihisrleverzis connected-through.rodilfi to the leg 'lzl oftthe generali incidence ball bearingcontroltsystem'35.

It will be seenthat when the. system '35. is made toislide'ialong the central shaft 21 the pitch angle of the blades willbe altered while the blades .remain free for lateral and vertical'oscillations.

In Fig. is shown in dotted lines at'l8 thearms of the'hula fi to which are attached the blades 1 carrying the propulsion units. Therefore Fig. 5 refers to the machine as shown in Fig. 2 in which twoblades I carry jet propulsion units and two others la are not driven.

'In Figs. 6, 7 and'8 is indicated in detail, how the blades carrying the propulsion units are mounted inside the hub.

' The root endof the blade I is continued in this case'by'only a'horizontal articulation 8%. Elastic stops Bl and Bid limit the vertical oscillations, which can-be reduced to any amplitude by interposing'additional elastic stops 85b. For the lateral attachment, generally no articulation is provided, but the attachment is made elastic in this example by means of elastic plates 82, 83.'fitted on both sides of the attachment bolts 84.

On the other side of the horizontal articulation 80 the plate 85 is fixed with the tube 86 entering and fitted inside the hub 6 as previously describedfor the blade la.

The pitch control of the-blades l is similar to thatfor the blades Ta but a separate ball bearing control-system 36 (Fig. 5) is provided in certaincases as previouslystated.

In order to reduce the pitch angle of all the blades! .and la, when an over-pressure tends to raise these blades, the horizontal articulation axis 2:, a: (Fig. 7) which was perpendicular to the longitudinal axis of the blades, can be set at an angle to it, such as $1, rm, (Fig. 8) in the direction of the rotation which is indicated by arrowg.

The horizontal articulation 68 of the blades la (Fig. 5) can be mounted in a similar way.

In Figs. 6, 7 and 8, the horizontal articulations 80 are indicated in two parts, which give astronger fitting in this lateral direction.

The .periodicalcontrol of the ailerons, which constitute the outer-part of theblades l, is as follows;

Fig. 5 shows how the wires 48 and 48a are pulled or released alternatively and periodically during one revolution of the rotor, when the control ball bearing system 40 is tilted in any direc-- tion around the universal joint articulations 4! and '42.

The wires 48 and 480. after crossing inside the blades 1 are attached to the double lever 88 and 88a fixed with a shaft 89 which is freeto rotate in supports 90 and etc, located in the interior of the aileron 9 (Figs. 9, l0 and 11) To the. same shaft 89 isv fixed a bevel wheel 9| which is therefore caused torotate alternatively in onedirection and the other during onerevolution when the wires 48 and 48a are operated.

Bevel wheel 91 engages with the bevel pinion 92 that is fixed with the shaft 93 which is freely journalled insupports 94 and 94a. Between these supports is fixed a lever 95 which passes through a slot 96 in the spar 91. The lever '85'is hingedly connected at 98 to the leading edge of the aileron 9.

This aileroniis mounted free to rotate around the tubular spar 91 of the blade and. it is obvious that its angle ofzincidencer willzbareguiated by the position of the lever 95 (Fig..1-1).

Whenthe bevel wheel.-9l is: alternatively operated the pinion 92 and hence the lever -il5mwill;

also be alternatively operated and in consequence, theaileron will have its pitch angle varied in one revolution from a maximum positive value to-a minimum. positive or negativevalue. l

When the blades 1a are operated so thattheir pitch angle is varied difierentially in one revolution in order to achieve the same results in place of the ailerons, the ballbearing system, which is universally movable on the double joint articulation 4| and 42, will have its operatingrods 43 connected to thelevers 15 which are secured to the end tubes ll of these blades (Fig. 5).

On the other hand, I have described howrthe pitch of all blades la is simultaneously variedby the ball bearing system 35 which is made to slide for that purpose along the shaftzl.

It is evident that in such a case these two ball bearing systems connected to the same lever'15 cannot operate separately.

Therefore, when the blades are acted differentially for stability purposes and simultaneously for the general variation of their pitch angle, a single ball bearing system is utilised in place of the system 35.

In Fig. 12 is shown how both these controls :can be operated by the same ball bearing system which can be universally hinged about and. simultaneously, slidable along the central shaft.

The control of the sliding movement of this system is identical with the control of the sliding movements of the other ball bearing systems, namely 23, 35, 36, 31- and38.

The ball bearing system 49a has now the interior joint articulation lla fixed to a sleeve 96 which can slide along the central shaft 21'.

The stability control lever 97 and the general pitch control lever 98 are located in the pilots cockpit at a far greater distance than is shown in the drawing.

As usual in aeroplanes, the longitudinal stability is achieved by the action on the wires 99 and 99a attached to lever 97 which is adapted to be operated forwards or backwards, while the lateral stability is achieved by operating the lever 91 to the left or to the right, thus operating the rod Hill in torsion. In reality, owing to the gyroscopic reaction of the rotor, the stability action will be at to the direction in which the upper system 40a is tilted.

The rod I90 is joined to another rod It! by means of a joint Hi2 which has to be as near as possible to lever 97 and-as far as possible from the central shaft 2?.

The wires 99, 98a, and the rods 163, Ill! operate respectively the levers Hi3 and its, which rotate freely on supports I55 and le -'3, both fixed with a sleeve I'll? capable of sliding freely along a vertical'shaft Hi8 fixed on the floor of the fuse I133. The levers Ill and H34 are respectively at tached the wires H2, HZa and H3, 3a all rising vertically. They are respectively attached to the ball bearing system at l l 4 and 4a,, and at right angles at H5 and 5a.

It is clear that when the lever '91 is operated,

the ball bearing system will hinge around its joint articulations Ma and 42a and the operating 9'" rods 43 will be raised and lowered during one revolution.

.To lever 98 is attached a rod H which is connected to a lever I I! that is fixed with a shaft I I8 and on which are fixed two levers H9 and I20. To lever II9 are attached two cable wires I2I, I2Ia which are crossed, and to lever I 20, two other wires I22, I22a which are not crossed. A The wire I2I passes freely through the ball bearing system and passes round the pulleys I23. H311 and is then attached at point I24 to the ball bearing system. The wire I2Ia extends between the attachment I24 and the lever I I9.

The wire I22 also passes freely inside the ball bearing system and round pulleys I25, [25a and then is attached to the ball bearing system at I26 which is opposite to the attachment I24. The wire I22a extends from the attachment I20 to the lever I20.

It is clear that when the lever 98 is moved for wards or backwards, the ball bearing system will be raised or lowered along the central shaft 21, and hence both operating rods 43 will have movement of the same magnitude, thus achieving an equal change in the pitch angle of the blades.

It is also clear from the drawing, that when this sliding movement is effected, the wires H2, H211 and H3, ll3a. will be operated, and that the latter operation will be possible only if the levers I04 and III, to which they are attached at their lower ends, can move upwards or downwards by the same length.

This is achieved by connecting the lower sleeve I01 to the levers H9 and I20 so that it can slide along the tube I08 at the same time and to the same extent as that of the ball bearing system along the shaft 21.

To lever H9 is attached the wire I2Ib which passes around the pulleys I 21 and I 21a and is then attached to an arm I28 carried by the sleeve I01. From the same arm extends another wire I2I c, in crossed relation to wire I2 Ib and then attached to the other end of lever I I 9.

In the same manner, but not crossed, are attached to lever I 20 the wires I 221), I220. Wire [22a is attached to an arm I 29, opposite the arm I28, and also fixed with sleeve I07. Then, is attached on the same point the wire I220, which passes round the pulleys I30, IBM. and from there directly to the other end of the lever I20.

It is clear to see that with this device, the sleeves 06 and I04 will slide equally and in the same direction, when the general pitch control lever 98 is operated by the pilot.

By reason of the position of the articulation I02 of the lateral control rods I00 and I! and of the pulleys I09, I09a guiding the longitudinal control wires 99, 99a the sleeve I01 can slide without materially affecting the lengths of these rods and wires although the necessary play, in practice very small, can be provided for.

The simultaneous rotation of the vertical rudder and 5a mounted at the rear of the fuselage is effected as follows: (Fig. 13).

The wires I40 and H011, which are operated in the usual way by the pilots feet, are attached to the lever I4I that is fixed with the tube I 42 which is freely rotatable around its vertical axis. A cranked lever I43 is also fixed to the same tube I42 and is attached by means of an articulated joint I44 near the bottom of the rudder 5.

Another lever I45, fixed with the upper part of the fuselage I, is connected to the control lever I46, attached to the rudder 5, by means of the rod I41 articulated at its two ends by means of spherical joints I48 and I49.

The rear part 5 of the rudder is hinged as usual on the other part 5a by meansof the'vertical articulations I50. The second part 5a, which in standard aeroplanes is fixed with the rear of the fuselage, is not fixed with the fuselage inthis case but can rotate around a horizontal axis 1:2, :m by its mounting onsupports I5I and I5Ia;

It can therefore be seen that when wire- I40 is, for example, pulled according to the arrow 72, the lever I4I will rotate according to arrow 1', and so will lever I43. Both of the rudders 5 and5a will rotate around ther horizontal hinges I5I and I5Ia, but as the part 5 is joined to the fuselage, which is a fixed point, by means of the levers I45 and I46 and the rod I4'l, part 5 will be obliged to rotate around the vertical hineesififl With this device the rudder achieves two distinct rotations, the first as a whole around a horizontal axis and the second for part 5 only around a vertical axis with reference to part 511.

The same result is achieved even when axis .112, m2 is not exactly horizontal, as it may happen in practice.

It is evident that the invention is not limited by the devices described and that other forms of mechanism can be utilized as long as the principles are not altered.

For example, the number of blades can be different from those indicated in Figs. 1 and 2.

The double articulation of the blades Ia and the method of articulating the blades I can be made in any different way.

The device for controlling in a difierential way the stability ailerons can be different.

The system described in order to concentrate on the same acting lever, the stability and gen eral incidence controls, can be different.

The same for the method which enables the double rotation around a vertical and around a horizontal axis of the vertical rudder, and for its position which can be elsewhere on the fuselage, namely in front.

The two axes around which the vertical rudder can swing, are not necessarily horizontal and vertical, respectively.

The upper double pulley system over which cross the various control wires can be replaced by levers.

The ball bearing control systems for the change of the pitch angle of the blades which has been described as separate for the blades carrying engines and those without, can be the same for both types of blades.

The joint control of the general incidence and the differential change of incidence on the same tube ending the blades can be efiected in many diiferent mechanical ways.

The blades I can also be articulated around a vertical axis, the elastic stops allowing, in this case, very small lateral displacement of these blades.

The whole system of wires which controls the ball-bearing systems, can be replaced by rigid tubes, preferably located one inside the other. In such a case each set of four wires operating one of these systems, is replaced by a single tube joined to the same control pin which slides along the central column.

The horizontal articulation of the blades 1 and m can advantageously be located so that the corresponding axes pass exactly through or lie 1 1 very near to the axis of i rotation of the propeller.

What I claim is:

A helicoptercomprising: a fuselage, a;- sustainingunit including a plurality of rotary'blades, jet propulsion units at the tips-0f 'at least some of said blades; amain liquid fuel tank insidethe fuselage, an auxiliary liquid fuel tanlialbove said blades" and in the vicinity-0f the axis of rotation of "the blades, fuel pipes iconnectedto said auxil iary feed tank to supply liquid fuelby gravity to the propulsion units on'the blade-tips andextending throughsaid blades for their whole length, and means to'ieed' fuel fiomthe main tank to the auxiliary tank.

VITTORIO' ISACCO;

REFERENCES CITED The following references" are of record in the file of this patent:

Number Number 12 UNITED 'S'IJ'illiiS v PATENTS Name Date. Taylor" June 26,1917 Isacco July 7, I931 Pitcairn .Sept. 1; 1931 Langdon Oct 31, 1933 Upson" Nov; 19, 1935 Kay et a1 Dec; 10, 1935 Plattp; Mar.'23,.1931 Howard Sept; 21', 1943 Gerhardt" Mar. 20, 1945 Dalton Nov. 16', 1948 FOREIGN. PATENTS Country Date= France Aug: 3, 1936 Great'Britaini of 1932 

